1. Field of the Invention
The present invention relates to an imaging device having an electronic viewfinder, to an electronic viewfinder for such an imaging device, and to a display control method.
2. Description of the Related Art
An imaging device fitted with an electronic viewfinder (hereafter abbreviated to “EVF”) is provided. A major feature of an EVF that has appeared in imaging devices with an EVF is that it is possible to confirm a photographic image beforehand. As a result, it has been possible to satisfy a user's need to get a rough idea of image brightness and color cast.
However, in recent years there has been more demand for an EVF and the need for much easier shooting has increased, such that with an EVF it is possible to perform playback of a photographic image with greater accuracy, it is possible to carry out various image adjustments on the EVF before shooting, and it is possible to confirm an image beforehand regardless of the environment.
As well as more accurate playback of taking images, color is an extremely important factor. However, color can be subject to change for various reasons. One of these reasons is the environment in which an image is confirmed. For example, for even a single printed image, in the case of viewing under a clear sky, white will appear white, while in the case of viewing under electric lighting white will take on something of a red hue. Specifically, even if the same image is viewed, the color cast of the image the person actually perceives on viewing will differ depending on the environment in which the image is viewed.
As a factor in reproducing color, there are differences depending on color adaptation of a person's eyes. For example, even for the same image, color cast in the case of viewing immediately after entering a dark room lit with electric light, and color cast in the case of viewing after a sufficient time has elapsed after entering a dark room, appear different. This is due to what extent the eyes become accustomed or acclimatized to the environment, and shows that in actual fact the color cast a person perceives may be different.
Also, as factors for reproducing color, besides the above factors the way in which color is seen also differs depending on an adaptive range (tracking range). For example, even for the same taken image, in the case of viewing under a clear sky on the case of viewing under a cloudy sky, there will not be too big a difference in how the color cast is perceived, but in the case of viewing under alight source of comparatively strong color cast, such as an electric light, differences in color cast will be perceived. This means that simultaneously with differences in environment in which an image is confirmed, there will be differences in the color cast that is actually perceived, depending on individuals and in what light source range a person's eyes perceive white as white.
Japanese patent laid open number 2002-290979 (hereinafter referred to as patent document 1) mentions color adaptation. In this patent document 1, there is disclosure of an idea for, regarding color fogging of a taken image arising in the case of shooting in a state where a white balance of a film that is used or white balance setting of a digital camera does not conform with the light source in which the image has been shot, confirming the extent of that color fogging in-situ. With patent document 1, inverse white balance processing is applied to image data for confirmation that is displayed on a rear surface liquid crystal display, based on light source information of the light source the image has been shot in and white balance setting, taking into consideration color adaptation for the shooting environment. Also, Japanese patent laid open number 2004-140736 (hereafter referred to as patent document 2) discloses changing the display color temperature so that in a case where a user has looked away from the subject and into the EVF, the user's eyes gradually become accustomed to the EVF display.
In patent document 1 described previously, at least color adaptation is dealt with, but in a case where the color of a taken image is confirmed on a rear surface liquid crystal display, simply reflecting color adaptation in the shooting environment in the color of image data used for confirmation is insufficient, and color will also vary depending on what white point has been set for the liquid crystal display that the image is displayed on.
To give a specific example, if it is assumed that shooting light source and white balance settings match, and a confirmation image is generated so as to match the taken image, the taken image white and the confirmation image white will match. However, if that confirmation image is displayed on a liquid crystal display panel having a red tinge (a display having a white point with a low color temperature), white of the confirmation image will be displayed with a red tinge. Also, if the confirmation image is displayed on a liquid crystal panel having a blue tinge (a display having a white point with a high color temperature), white of the confirmation image will be displayed with a blue tinge. Accordingly, the technology disclosed in patent document 1 cannot provide sufficient solution to the current problem with an EVF.
Also, the above described differences in the way color cast is perceived have a significant effect on reproduction of color of a taken image on an EVF. However, current EVFs have not taken this point into consideration, and as a result, while it is possible to reproduce color comparatively close to that of the taken image under particular confirmation conditions, there may be situations where the image appears tinged with blue or tinged red depending on the environment. This is disruptive to the photographer, and impairs the image of the photographer, and impedes them in shooting comfortably. Accordingly, with the conventional EVF accurate reproduction of a taken image regardless of the environment was not possible, and also it was not possible to perform various image adjustments to enable accurate shooting while viewing on the EVF to shoot accurately, and the taking of a photograph could not be performed accurately.
This can be solved to a certain extent by gradually changing display color temperature, as in patent document 2 described above. However, since a person's eyes can only adapt to color temperature of the environment to a certain extent, variation in display color temperature is preferably not performed without considering that color adaptation range.